主卡对附卡设定的笔交易额度（）月交易额度。
A、不能低于
B、必须高于
C、必须低于
D、不能高于
参考答案：D
已知在△ABC中，∠ACB=90°，CD是AB边上的高，∠B=30°，AD=a，则AB=______．
His pants are white and red. His shirt is green and yellow. He looks _____ . [ ]
A. thin
B. cold
C. colourful
D. tall
